When we wake up in the morning, there is a fur-like coating on our teeth: this is a biological film that forms overnight. Over time, this can lead to the development of caries – which is why it is critical that we remove this “rug” using a toothbrush. There is a large selection of dental hygiene products on the market, including brushes whose bristles are rounded, pointed, hard, and soft. There are also brushes with bristles of varying lengths. Until now, to determine which ones clean the most thoroughly while doing as little damage to the tooth enamel as possible, manufacturers have had to conduct experiments. This was also the case when selecting the right abrasive particles to be used in toothpastes. Various toothpaste formulations had to be mixed and then tested on artificial tooth enamel models – a laborious task. Another drawback to this approach is the fact that the brush, paste and enamel can be analyzed only as a complete system, which means that manufacturers have a difficult time determining which effects observed in these experiments are derived from which of the various parameters.
Simulated tooth brushing
Help has arrived in the form of a new type of simulation developed by researchers at the Fraunhofer Institute for Mechanics of Materials IWM in Freiburg. “With our procedure, manufacturers of dental hygiene products can determine the cleaning effectiveness of each individual parameter in a fast, economical and reliable manner,” says IWM scientist Dr. Christian Nutto. “Unlike in real-world experiments, the individual parameters in the simulation can be easily modified – be it the size, shape and quantity of abrasive particles in a toothpaste, or the material from which they are made, or the shape and elasticity of the bristles.” We can increase the scope of the experiments far beyond what is possible in real-world testing, and that makes a noticeable difference in the quality of the products. What effects do the shape and stiffness of the bristles have when brushing? How do the different abrasives or toothpaste viscosity affect the enamel, and how do they affect their intended target, the biofilm on the teeth? Simulation testing can deliver reliable answers to questions such as these, and it does so long before the manufacturer ever mixes the toothpaste.